Apparatus for measuring imbalance forces of a tire/hub assembly of a vehicle during motion of the vehicle

ABSTRACT

An apparatus configured to be removably attached to a tire/hub assembly of a vehicle via lug nuts of the tire/hub assembly is used to determine imbalance forces of the tire/hub assembly during motion of the vehicle. The apparatus includes a disk and a plurality of cup-shaped objects fixed at one end to the disk and extending perpendicularly outward from the disk. The plurality of cup-shaped objects are arranged a fixed radial distance from a radial center of the disk in a pattern that matches the lug nuts of the tire/hub assembly. The apparatus is mounted to the vehicle&#39;s tire/hub assembly by fitting the plurality of cup-shaped objects over the lug nuts of the tire/hub assembly. The apparatus further includes one or more inertial measurement units (IMU&#39;s) mounted to the disk to measure parameters that are used for calculating the imbalance forces during motion of the vehicle.

BACKGROUND OF THE INVENTION

“Tire balance” refers to distribution of mass within a vehicle tire orthe entire wheel, including the rim, on which the vehicle tire ismounted. Tire balance may also be referred to as “tire unbalance” or“tire imbalance.” As described in U.S. Pat. No. 6,595,053 (Parker),which is incorporated by reference herein, the balancing of vehiclewheel assemblies is most often accomplished by removing the tire/wheelassemblies from the vehicle and mounting each of the tire/wheelassemblies on an off-car-balancer. The off-car balancer rotates thetire/wheel assembly, measures the imbalance forces and displays theamount and location of weight to add to the wheel to bring thetire/wheel assembly into a balanced condition. One example of an off-carbalancer is The Road Force® Elite wheel balancer, which is commerciallyavailable from Hunter Engineering Company, Bridgeton, Mo.

As also described in U.S. Pat. No. 6,595,053, a tire/wheel assembly maybe balanced so that it produces negligible forces when rotated on theoff-car balancer, but the same assembly may cause significant imbalanceforces when mounted on the vehicle and rotated using the vehicle'sbearings and axle. The imbalance forces of a tire/wheel assembly willremain constant between the off-car balancer and the vehicle only if therelationship between the tire/wheel assembly and the axis of rotation isthe same for the two mountings. Achieving the desired on-car wheelbalance with only an off-car balancer involves both accurately mountingthe wheel on the balancer and then accurately mounting the tire/wheelassembly on the vehicle's hub. Possible causes of wheel-to-vehiclemounting inaccuracy include clearance between the balancer hub and therim pilot hole, runout of the hub pilot diameter or mounting face, rustor grime between rim and vehicle hub, runout in studs and runout in lugnuts.

As further described in U.S. Pat. No. 6,595,053, on-car balancers caneliminate some of the mounting accuracy problems by performing thebalance measurements after the tire/wheel assembly is in its finalmounted position on the vehicle. Although on-car balancers areavailable, they are not very popular because of setup difficulties,operational limitations, and safety issues.

Despite the many efforts made by the industry, including those describedin U.S. Pat. No. 6,595,053, there still remains an unmet need for anon-car balancer that is inexpensive, convenient to use, and which cancapture parameters necessary for calculating imbalance forces when thevehicle is actually in motion. The present invention fulfills such aneed.

SUMMARY OF THE PRESENT INVENTION

In one preferred embodiment, the present invention provides an apparatusconfigured to be removably attached to a tire/hub assembly of a vehiclevia lug nuts of the tire/hub assembly for use in determining imbalanceforces of the tire/hub assembly during motion of the vehicle. Theapparatus includes a disk, a plurality of cup-shaped objects, and one ormore inertial measurement units (IMU's). Each cup-shaped object isrigidly fixed at one end to the disk and extends perpendicularly outwardfrom the disk. The plurality of cup-shaped objects are arranged a fixedradial distance from the radial center of the disk in a pattern thatmatches the lug nuts of the tire/hub assembly. Each cup-shaped object ishollow along at least a portion of its length that is distal from thedisk. The hollow portion has a diameter that is larger than a diameterof the lug nuts of the tire/hub assembly so as to allow the apparatus tobe mounted to the vehicle's tire/hub assembly by fitting the pluralityof cup-shaped objects over the lug nuts of the tire/hub assembly. Theone or more IMU's are mounted to the disk and are configured to measureparameters that are used for calculating the imbalance forces duringmotion of the vehicle. One or more of the cup-shaped objects may includea magnet fixedly mounted at an end of the cup-shaped objects that isproximate to the disk so as to magnetically engage with one of the lugnuts when the apparatus is attached to the tire/hub assembly of avehicle, and thereby inhibit the apparatus from coming off of thevehicle when the vehicle is in motion.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described byway of example with reference to the accompanying drawings:

FIGS. 1A-1D show a disk for use with the apparatus of the presentinvention.

FIGS. 2A-2C show details of cup-shaped objects for use with theapparatus, and also show details of how the cup-shaped objects areattached to the disk.

FIG. 2D show details of how the cup-shaped object is fit over a lug nut.

FIG. 2E shows a partial view of an alternative assembly for rapidlyattaching the disk to a tire/hub assembly.

FIG. 3A shows prior art tire/hub assemblies.

FIGS. 3B and 3C show how the apparatus of the present invention engagesa tire/hub assembly.

FIGS. 4A and 4B show a single, center-mounted IMU of the assembly.

FIGS. 5A and 5B show an alternative embodiment of the assembly havingmultiple IMU's.

FIGS. 6A-6L show alternative embodiments of the present invention havinga floating center shaft assembly and a single IMU mounted to a radialcenter of the floating center shaft assembly.

FIGS. 7A-7C show an alternative embodiment of the apparatus havingcup-shaped objects that are friction-fit to the lug nuts.

FIGS. 8A and 8B show a cover that may be placed over the wheel-mountedassembly of FIGS. 6A-6F.

DETAILED DESCRIPTION OF THE INVENTION

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the present invention.

The words “a” and “an”, as used in the claims and in the correspondingportions of the specification, mean “at least one.”

A general overview of one preferred embodiment is described with respectto FIGS. 3A, 3B, 3C, 4A and 4B. FIG. 4B shows a fully assembledapparatus configured to be removably attached to a tire/hub assembly ofa vehicle via lug nuts of the tire/hub assembly for use in determiningimbalance forces of the tire/hub assembly during motion of the vehicle.The tire/hub assembly and its corresponding lug nuts 304 are best shownin FIG. 3B. In FIGS. 3B and 3C, element 310 represents a center cutawayof a vehicle rim which is part of the tire/hub assembly. FIG. 3A showstwo conventional hub assemblies that may form part of the tire/hubassembly. The upper diagram of FIG. 3A shows a hub with studs,collectively, labeled as 300. A lug nut 304 is attached to a distal endof each stud. The lower diagram of FIG. 3A shows a hub with threadedholes, collectively, labeled as 302. A lug bolt 306 is attached to eachthreaded hole. Not shown in FIGS. 3A and 3B is the tire which is locatedbetween the hub 300 and the lug nuts 304 in the upper diagram of FIG.3A, and between the hub 302 and the ends of the lug bolts 306 in thelower diagram of FIG. 3B. As described herein, the lug nuts 304 performthe same function as the lugs at the end of the lug bolts 306, and thusthey can be considered as equivalent elements.

Referring again to FIGS. 3B, 3C, 4A and 4B, one preferred embodiment ofthe apparatus in the present invention includes an assembly of thefollowing elements:

i. a disk 100 (generally cylindrical plate),

ii. a plurality of cup-shaped objects 202 (also, interchangeablyreferred to herein as “cups 202,” and

iii. one or more IMU's 406 (an IMU may also be referred to as an “IMUsensor”).

The disk 100 has an outer facing surface 120 and an inner facing surface122 (labeled in FIG. 2C). The inner facing surface 122 faces the hub 300when the apparatus is mounted to the vehicle's tire/hub assembly.

FIGS. 3B and 3C show a partially assembled apparatus that includes thedisk 100 and the cup-shaped objects 202, whereas FIGS. 4A and 4B showall of the above-listed elements i.-iii. In each of these figures, thedisk 100 and the cup-shaped objects 202 are part of an overall assembly230 of thumbscrew 132, cup 202, magnet 204, magnet capture ring 206, andthe appropriately sized adapter 210, 212, or 214, all of which aredescribed in more detail below.

Each cup-shaped object 202 is rigidly fixed at one end to the disk 100and extends perpendicularly outward from the disk 100. The plurality ofcup-shaped objects 202 are arranged a fixed radial distance from theradial center of the disk 100 in a pattern that matches the lug nuts 304of the tire/hub assembly. Each cup-shaped object 202 is hollow along atleast a portion of its length that is distal from the disk 100. Thehollow portion has a diameter that is slightly larger than a diameter ofthe lug nuts 304 of the tire/hub assembly so as to allow the apparatusto be mounted to the vehicle's tire/hub assembly by fitting theplurality of cup-shaped objects 202 over the lug nuts 304 of thetire/hub assembly, as best illustrated in FIGS. 3B and 3C. The one ormore IMU's 406 are mounted to the disk 100, as best illustrated in FIGS.4A and 4B, and are configured to measure parameters that are used forcalculating the imbalance forces during motion of the vehicle. In theembodiment of FIGS. 4A and 4B, a single IMU 406 is mounted in a centerof the disk 100. Other embodiments that use multiple IMU's are describedbelow with respect to FIGS. 5A and 5B.

The one or more IMU's 406 may be mounted to the disk 100 in any suitablemanner. In the embodiment of FIGS. 4A and 4B, the single IMU 406 ismounted to the outer facing surface 120 of the disk 100 via IMU housing402. The IMU housing 402 has a rectangular-shaped slot 410 and mountingplate 412 formed as one piece. The mounting plate 412 is attached viascrews 404 to a center portion of the outer facing surface 120 of disk100. The slot 410 receives the IMU 406, as illustrated in FIG. 4A whichshows the IMU 406 exploded from the slot 410, and FIG. 4B which showsthe IMU 406 fully inserted into the slot 410. The IMU 406 is securelyretained in the slot 410 by any suitable means, such as friction fit,clamps, holding screws, or hook and loop fastener material.

FIGS. 5A and 5B show another embodiment of the apparatus wherein thereare three IMU's 510 arranged in an equilateral triangle configuration,wherein each IMU is equidistant from the center of the disk 100. In thismanner, each IMU is placed at 120 degree angles from the center of thedisk 100. FIG. 5A shows one mounting embodiment wherein the three IMU's510 are fixed to mounting flange 504, which is then attached to mountingplate 512 via a center hole 513 in the mounting plate 512. FIG. 5B showsthe fully assembled view.

Lug nut configurations differ among vehicles in at least the followingways:

i. number of lug nuts

ii. diameter of the lug nuts

iii. radial distance of the lug nuts from the center of the hub

iv. lug patterns, namely, the arrangement of lug nuts along the fixedradius from the center of the hub (typically equidistant, but notalways)

These parameters result in a large number of permutations of potentiallug nut configurations. However, there are a handful of well-knownconfigurations that cover a large percentage of vehicles. The assemblyhas various features to allow for its use with many different commonconfigurations, as described below.

FIG. 1A shows the disk 100 by itself. The disk 100 includes a centeropening 112 and device mounting holes 114 for receiving the screws 404shown in FIGS. 4A, 4B, 5A, and 5B. The disk also includes the followingslots:

i. slot 102 for use with a 4, 5, or 6 lug patterns

ii. slot 104 for use with 4 and 6 lug patterns

iii. slot 106 for use with 5 lug patterns

iv. slot 108 for use with 6 lug patterns

v. slot 110 for use with 4 lug patterns

The various lug patterns are also represented by letters A, B, and C.

To allow for interchangeability, the cup-shaped objects 202 areremovably attachable to the disk 100 to allow a set of cup-shapedobjects 202 to be reconfigured on the disk 100 to match the appropriatelug nut configuration for a particular vehicle. Likewise, different setsof cup-shaped objects 202 can be provided having different diameters toaccommodate different diameter lug nuts 304. The slots 102-100 allow forchanging the radial distance of the lug nuts from the center of the hub,as opposed to providing holes that would only accommodate one radialdistance.

FIGS. 1B-1D show thumbscrews 132 which are used to fasten the cup-shapedobjects 202 to the disk 100, as described below. FIG. 1B shows a 4 lugpattern that requires four thumbscrews 132 (one for each cup-shapedobject 202), FIG. 1C shows a 5 lug pattern that requires fivethumbscrews 132 (one for each cup-shaped object 202), and FIG. 1D showsa 6 lug pattern that requires six thumbscrews 132 (one for eachcup-shaped object 202).

FIGS. 2A-2D show additional details of the cup-shaped objects 202, andthey also show details of how the cup-shaped objects 202 are attached tothe disk 100. The example in FIGS. 2A-2D uses the 5 lug pattern of FIG.1B. FIG. 2A is an exploded top view of the apparatus, FIG. 2B is a fullyassembled top view of the apparatus, FIG. 2C is fully assembled bottomview of the apparatus, and FIG. 2D is an exploded view of different lugnut adapters (described below) for use with the cup-shaped object 202.

FIG. 2A shows five thumbscrews 132 which are used to fasten fivecup-shaped objects 202 to the disk 100. Each thumbscrew 132 is insertedthrough an appropriate slot 102 or 106 associated with the 5 lug patternof FIG. 1B, and is screwed into threaded holes 224 shown in phantom in acenter of a distal portion of each cup-shaped object 202. When fullyscrewed in, a flange of each thumbscrew 132 is flush against the outerfacing surface of the disk 100, and each thumbscrew 132 securely holdsits respective cup-shaped object against the inner facing surface 122 ofthe disk 100, as shown in FIG. 2C.

FIG. 2A also shows magnet 204, magnet capture ring 206, and lug nutadapter 208 that are received inside each of the respective cup-shapedobjects 202. The magnet 204 and magnet capture ring 206 form a magnetassembly 207 that is placed in a pocket area of the cup-shaped object202 so as to be flush against a distal end surface of the cup-shapedobject 202 (top portion of the cup-shaped object 202 when viewed in FIG.2A, bottom portion of the cup-shaped object 202 when viewed in FIG. 2B).The magnet 204 is thus fixedly mounted at an end of the cup-shapedobject 202 that is proximate to the disk 100. The magnet assembly 207 isheld in place within the cup-shaped object 202 by friction fit. Adhesivemay alternatively be used for this purpose. In use, the magnets 204magnetically engage with the lug nuts 304 when the apparatus is attachedto the tire/hub assembly of a vehicle, and thereby inhibit the apparatusfrom coming off of the vehicle when the vehicle is in motion. In onepreferred embodiment, there is a magnet 204 in each cup-shaped object202. However, depending upon the strength of the magnets 204, it may notbe necessary to provide magnets 204 in each cup-shaped object.

FIG. 2A also shows a lug nut adapter mounted inside each cup-shapedobject 202. As discussed above, lug nuts come in a variety of differenthead diameters. To avoid excessive play when the apparatus is attachedto the tire/hub assembly of a vehicle, an appropriately sized hollow lugnut adapter 208 is selected for the lug nuts of the vehicle so as toprovide a snug fit, but not necessarily a friction fit. This also helpsto ensure that IMU 406 or IMU's 510 are symmetrically arranged withrespect to a center axis of the tire/hub assembly. The lug nut adapter208 may be removable to allow for different sized adapters to be usedwith the same cup-shaped object 202 and may be held in place within thecup-shaped object 202 by friction fit. Alternatively, the lug nutadapter 208 may be permanently assembled within the cup-shaped object202. If so, different cup-shaped objects 202 will be required for lugnuts of different head diameters.

The cup-shaped objects (cups) 202 have a depth of length, labeled as “L”in the leftmost cup 202 of FIG. 2A that is sufficient to accommodate athread portion for receiving the thumbscrew 132, the magnet assembly207, and the full depth of the lug nut 304.

FIG. 2B is a fully assembled top view of the apparatus of FIG. 2A, andFIG. 2C is a fully assembled bottom view of the apparatus of FIG. 2A. InFIGS. 2B and 2C, element 230 refers to the assembly of the thumbscrew132, cup 202, magnet 204, magnet capture ring 206, and the appropriatelysized adapter 210, 212, or 214.

FIG. 2D shows examples of three different lug nut adapters 210, 212 and214 for use with the same cup-shaped object 202. The uppermost diagramshows lug nut adapter 210 for accommodating a 17 mm lug nut 216, themiddle diagram shows a lug nut adapter 212 for accommodating a ⅞ inchlug nut 218, and the bottommost diagram shows a lug nut adapter 214 foraccommodating a 15/16 inch lug nut 222. The lug nut adapters 210, 212and 214 provide the same functionality as the lug nut adapter 208described above and shown in FIG. 2A.

FIG. 2E shows a partial view of an alternative assembly for rapidlyattaching disk 100 to a tire/hub assembly when time-is-of-the-essence,particularly when interchangeability is due to different vehicles andvarying hub/lug configurations are sequentially encountered and thethreading and/or unthreading of thumbscrews, nuts, and cups, isimpractical and labor intensive. Cup 202 still contains magnet 204,magnet capture ring 206, and may or may not require lug nut adapter 208for attachment to vehicle lug nuts. Instead of a threaded type ofattachment as shown in FIG. 2A, FIG. 2E shows cup 202 having an affixedcylindrical shaft 234 that passes through slot 106 of disk 100.Magnetically locking cylinder 240 is pressed onto cylindrical shaft 234through hole 236 and is firmly held in place because the disk facingsurface 238 of the ring magnet 242 is the opposite polarity of the diskfacing surface 232 of magnet 204, thereby producing a strong magneticclamp. All contact surfaces of cup 202, disk 100, and magnetic lockingcylinder 240 may have abrasive or geometrically opposite mating surfacesto decrease lateral slippage when magnetically clamped.

The materials for constructing certain parts of the apparatus such asthe disk 100, cup-shaped objects 202, and IMU housing 402 are preferablyrigid and durable so as to withstand movement on a vehicle with minimalplay. One suitable material is a thermoplastic polymer, such asacrylonitrile butadiene styrene (ABS). The selected material must alsonot cause interference with the electronics of the IMU's. ABS haselectrical insulation properties that are well-suited to the operatingenvironment of the apparatus.

FIGS. 7A-7C show another embodiment of the apparatus of the presentinvention that includes an assembly of the following elements:

i. disk 100 (generally cylindrical plate),

ii. a plurality of cup-shaped objects 202, and

iii. one or more IMU's 406 (an IMU may also be referred to as an “IMUsensor”).

The embodiment of FIGS. 7A-7C differs from the embodiment describedabove in that the disk 100 and the cup-shaped objects 202 are preferablyformed as a single unit, such as by injection molding. Since thecup-shaped objects 202 are not removable, the single unit will belimited in use to a particular lug nut pattern. However, fabricationcosts may be lower due to the reduced number of parts, the eliminationof any need for creating slots in the disk 100, and the relativeinexpensiveness of injection molding. The remaining parts of theapparatus of FIGS. 7A-7C are the same as the embodiment described below,namely, the IMU housing 402 that is mounted to the single unit viascrews 404, and that receives the IMU 406, as illustrated in FIGS. 7Band 7C. Alternatively, the single unit may have the multiple IMUembodiment shown in FIGS. 5A and 5B attached thereto.

The embodiment of FIGS. 7A-7C also differs from the embodiment describedabove in that the cup-shaped objects 202 are designed to be friction fitover the lug nuts 304 of the vehicle, or over only a subset of the lugnuts of the vehicle. For example, various models of the Ford® F150 truckhave a six lug pattern. The embodiment of FIGS. 7A-7C provides fourcup-shaped objects 202 that friction fit over four of the six lug nuts304 in a manner similar to a conventional decorative center cap that iscommercially available for such a vehicle. Instead of using magnetsinside of the cup-shaped objects 202 for releasably attaching theapparatus to the lug nuts 304, the cup-shaped objects 202 include aplurality of slits or slots 700 which allow sidewall sections 702 ofeach cup-shaped object 202 to slightly flex outward to provide thefriction fit. In the embodiment shown in FIGS. 7A-7C, each cup-shapedobject 202 has four slits or slots 700 that define four sidewallsections 702.

The embodiment of FIGS. 7A-7C may also be able to accommodate differentsized lug nut adaptors, such as illustrated in FIG. 2D. However, forsuch adaptors to work, the adaptors are preferably also constructed withmatching slits or slots that align with the slits or slots 700 of thecup-shaped object 202, so that the sidewalls of the two parts (i.e., theadaptor and the cup-shaped object 202) slightly flex outward in unisonto provide the friction fit.

In the embodiments described above, the IMU's are rigidly attached tothe disk 100 so that they rotate with the disk 100 when the vehicle isin motion.

In alternative embodiments, the IMU's are mounted to the disk 100 in amanner that allows them to remain relatively stationary, in a mannersimilar to a hubometer (also, known as a hubodometer). These embodimentsare referred to more generally as having a “non-rotating IMU” and ashaving a “floating center shaft assembly.” These embodiments are alldescribed with respect to a single IMU 406 mounted in a center of thedisk 100. For ease of nomenclature, the combination of the disk 100 andthe cup-shaped objects 202 is referred to as “wheel-mounted assembly602.”

FIGS. 6A-6C show one embodiment of an apparatus 600 that includes anon-rotating IMU/floating center shaft assembly. A floating center shaft616 extends through a center of the wheel-mounted assembly 602. Two setsof bearings 612, shown in phantom in FIGS. 6B and 6C, are providedwithin the floating center shaft 616. The bearings 612 are inside ofbearing cap 620. A weight stabilization assembly 614 includes a hubportion 615 that is attached to the distal end of the floating centershaft 616, a downward facing shaft 617 (meaning, downward facing when inoperation) which can be rigid or flexible, and a contoured weight 618fixed to a distal end of the downward facing shaft 617. A top view ofthe contoured weight 618 is also shown in a separate figure within FIGS.6B and 6C. The non-rotating IMU 406 is attached to weight stabilizationassembly 614 in the center of wheel-mounted assembly 602, as shown inphantom in FIG. 6A.

In one preferred embodiment, the disk portion of the wheel-mountedassembly 602 further includes a pair of magnets 622 mounted thereon inan opposed manner along a radial line extending through the radialcenter of the wheel-mounted assembly 60, that is, a fixed radialdistance from the radial center of the disk portion. In this embodiment,the IMU 406 further includes a Hall effect sensor (not shown) that worksin conjunction with the magnets to measure rotational speed of thewheel-mounted assembly 602 during motion of the vehicle.

FIG. 6A is a front elevation view of the apparatus 600. FIG. 6B is aside elevation view of the apparatus 600 and shows the weightstabilization assembly 614 exploded from the wheel-mounted assembly 602and the floating center shaft 616. FIG. 6C is also a side elevation viewof the apparatus 600 and shows the weight stabilization assembly 614attached to the wheel-mounted assembly 602 and the floating center shaft616.

FIGS. 6D-6F show another embodiment of an apparatus 630 that alsoincludes a non-rotating IMU/floating center shaft assembly. Thisembodiment is similar to the embodiment of FIGS. 6A-6C, except that itrelies upon an airfoil stabilizing structure 634, instead of the weightstabilization assembly 614, for stabilization of the IMU 406. Theairfoil stabilizing structure 634 comprises hub portion 636 and airfoil632. The hub portion 636 and the airfoil 632 perform comparablefunctions as the hub portion 615 and the contoured weight 618 of theembodiment in FIGS. 6A-6C. The geometry of the airfoil stabilizingstructure 634 is an example representation only.

FIG. 6D is a front elevation view of the apparatus 630. FIG. 6E is aside elevation view of the apparatus 630 and shows the airfoilstabilizing structure 634 exploded from the wheel-mounted assembly 602and the floating center shaft 616. FIG. 6C is also a side elevation viewof the apparatus 600 and shows the airfoil stabilizing structure 634attached to the wheel-mounted assembly 602 and the floating center shaft616.

FIGS. 6G-6I show another embodiment of an apparatus 640 that alsoincludes a non-rotating IMU/floating center shaft assembly. Thisembodiment includes both of the stabilizing structures shown in FIGS.6A-6C and 6D-6F. These figures are thus self-explanatory in view of thedescriptions above of the two respective embodiments. The same hubportion is used for both stabilizing structures, and thus this elementis labeled as hub portion 615/636. The three different views in FIGS.6G-6I are similar to the three different views of FIGS. 6A-6C and 6D-6F,and thus are not described further. The embodiment of FIGS. 6G-6I isalso shown with the magnets 622.

FIG. 6J shows a front and side elevation view of only the weightstabilization assembly 614 used in FIGS. 6A-6C. FIG. 6K shows a frontand side elevation view of only the airfoil stabilizing structure 634used in FIGS. 6D-6F. FIG. 6L shows a front and side elevation view ofthe combined weight stabilization assembly 614 and airfoil stabilizingstructure 634 used in FIGS. 6G-6I.

FIGS. 8A and 8B show a clear cover 800 that may be placed over thewheel-mounted assembly 602 shown in FIGS. 6A-6C to reduce roadturbulence that may cause the stationary IMU 406 to oscillate. The cover800 may be secured to the wheel-mounted assembly 602 via cover tabs 802that are molded into cover 800. A similar type of cover 800 may also beused with the embodiment FIGS. 6D-6F. The cover tabs 802 snap over theback of the wheel-mounted assembly 602 to secure it in place. Inside ofthe cover 800, approximately ⅜″ from the opening, are three raised stops804 that rest on the front side of the wheel-mounted assembly 602. Thestops 804 keep the cover 800 in the required position over thewheel-mounted assembly 602, preventing the cover 800 from making contactwith the weight stabilization assembly 614.

In one preferred embodiment, the cup-shaped objects 202 arecylindrically shaped, and define cylinders having solid circumferentialsidewalls. However, the cup-shaped objects 202 can have other shapes,such as square or octagonal, since other shapes would still allow themto releasably engage lug nuts, particularly when using the magneticattachment embodiment. Likewise, the lug nut adapters may have asuitable internal diameter shape so as to snugly fit over the lug nuts,while having a different external diameter shape to conform to the shapeof the cup-shaped objects 202.

In selected embodiments disclosed above, the cup-shaped objects 202 arerigidly fixed to the disk 100 via threaded bolts, such as thumbscrews.However, other ways to fasten the cup-shaped objects 202 to the disk 100are within the scope of the invention, such as nuts and bolts, andadhesives. In an alternative embodiment, an integrally formed thread mayextend from a distal end of the cup-shaped object 202, and thecup-shaped object 202 may be fastened to the disk by inserting thethread through the hole in the disk 100 and fastening it using a nut onthe opposite side of the disk 100.

In other embodiments, such as shown in FIGS. 7A-7C, the cup-shapedobjects 202 and the disk 100 are formed as a unitary piece, and thus nofastening mechanism is needed.

The magnetic attachment embodiment is only one preferred structure forremovably attaching the apparatus to the tire/hub assembly of thevehicle via the lug nuts of the tire/hub assembly. The scope of thepresent invention includes other attachment mechanisms that rely uponphysical (as opposed to magnetic) attachment of the apparatus to thetire/hub assembly of the vehicle via the lug nuts of the tire/hubassembly, such as clamping mechanisms, and other types of physicalfastening mechanisms.

Any IMU may be used that has a form factor and durability suitable forthe environment described herein. One suitable IMU is the IMU describedin U.S. Pat. No. 10,284,752 (Canfield et al.), which is incorporatedherein by reference. Sample measured parameters that are used forcalculating the imbalance forces during motion of the vehicle include,and which are captured by the IMU's include, but are not limited to,acceleration and angular rotation. The data captured by the IMU may thenbe used for at least the following purposes:

i. Determine where correction weights should be attached to the rim ofthe wheel to achieve improved balancing of the tire/hub assembly.

ii. Determine if the tire/hub assembly is so far out of balance thatnormal balancing (adding of correction weights) cannot correct theimbalance.

In use, the different embodiments of the apparatuses (referred to hereinin the singular) are removably attached to a tire/hub assembly of avehicle via lug nuts of the tire/hub assembly. The vehicle is thendriven on a road surface, and during motion of the vehicle, parametersmeasured by the one or more inertial measurement units (IMU's) mountedto the disk of the apparatus are collected, and then subsequently usedfor calculating the imbalance forces.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention.

What is claimed is:
 1. An apparatus configured to be removably attachedto a tire/hub assembly of a vehicle via lug nuts of the tire/hubassembly for use in determining imbalance forces of the tire/hubassembly during motion of the vehicle, the apparatus comprising: (a) adisk; (b) a plurality of cup-shaped objects, each cup-shaped objectbeing rigidly fixed at one end to the disk and extending perpendicularlyoutward from the disk, the plurality of cup-shaped objects beingarranged a fixed radial distance from a radial center of the disk in apattern that matches the lug nuts of the tire/hub assembly, each of thecup-shaped objects being hollow along at least a portion of its lengththat is distal from the disk, the hollow portion having a diameter thatis larger than a diameter of the lug nuts of the tire/hub assembly so asto allow the apparatus to be mounted to the vehicle's tire/hub assemblyby fitting the plurality of cup-shaped objects over the lug nuts of thetire/hub assembly; and (c) one or more inertial measurement units(IMU's) mounted to the disk and configured to measure parameters thatare used for calculating the imbalance forces during motion of thevehicle, wherein one or more of the cup-shaped objects includes a magnetfixedly mounted at an end of the cup-shaped objects proximate to thedisk so as to magnetically engage with one of the lug nuts when theapparatus is attached to the tire/hub assembly of the vehicle, andthereby inhibit the apparatus from coming off of the vehicle when thevehicle is in motion.
 2. An apparatus configured to be removablyattached to a tire/hub assembly of a vehicle via lug nuts of thetire/hub assembly for use in determining imbalance forces of thetire/hub assembly during motion of the vehicle, the apparatuscomprising: (a) a disk; (b) a plurality of cup-shaped objects, each ofthe cup-shaped objects being rigidly fixed at one end to the disk andextending perpendicularly outward from the disk, the plurality ofcup-shaped objects being arranged a fixed radial distance from a radialcenter of the disk in a pattern that matches the lug nuts of thetire/hub assembly, each of the cup-shaped objects being hollow along atleast a portion of its length that is distal from the disk, the hollowportion having a diameter that is larger than a diameter of the lug nutsof the tire/hub assembly so as to allow the apparatus to be mounted tothe vehicle's tire/hub assembly by fitting the plurality of cup-shapedobjects over the lug nuts of the tire/hub assembly; and (c) a pluralityof inertial measurement units (IMU's) mounted to the disk and configuredto measure parameters that are used for calculating the imbalance forcesduring motion of the vehicle, wherein the plurality of IMU's are mountedto the disk a fixed radial distance from the radial center of the diskin an evenly spaced pattern, and wherein the plurality of IMU's rotatewith the disk during motion of the vehicle.
 3. An apparatus configuredto be removably attached to a tire/hub assembly of a vehicle via lugnuts of the tire/hub assembly for use in determining imbalance forces ofthe tire/hub assembly during motion of the vehicle, the apparatuscomprising: (a) a disk; (b) a plurality of cup-shaped objects, each ofthe cup-shaped objects being rigidly fixed at one end to the disk andextending perpendicularly outward from the disk, the plurality ofcup-shaped objects being arranged a first fixed radial distance from aradial center of the disk in a pattern that matches the lug nuts of thetire/hub assembly, each of the cup-shaped objects being hollow along atleast a portion of its length that is distal from the disk, the hollowportion having a diameter that is larger than a diameter of the lug nutsof the tire/hub assembly so as to allow the apparatus to be mounted tothe vehicle's tire/hub assembly by fitting the plurality of cup-shapedobjects over the lug nuts of the tire/hub assembly; (c) a floatingcenter shaft assembly attached to the disk; and (d) a single inertialmeasurement unit (IMU) mounted to a radial center of the floating centershaft assembly and configured to measure parameters that are used forcalculating the imbalance forces during motion of the vehicle, whereinthe floating center shaft assembly inhibits rotational movement of thesingle IMU during motion of the vehicle.
 4. The apparatus of claim 3wherein the disk includes a plurality of holes that define a lug nutpattern so as to allow the plurality of cup-shaped objects to be rigidlyfixed to the disk in locations that correspond with the lug nut pattern.5. The apparatus of claim 4 wherein each of the cup-shaped objectsincludes a hole at the one end, and each of the plurality of cup-shapedobjects are removably attached to the disk via a fastener extendingthrough one of the holes in the disk and also through the hole at theone end of the cup-shaped object.
 6. The apparatus of claim 5 whereinthe fastener is a threaded bolt, and the hole in the one end of thecup-shaped object includes threads for receiving the threaded bolt. 7.The apparatus of claim 3 wherein the cup-shaped objects arecylindrically shaped.
 8. The apparatus of claim 7 wherein the cup-shapedobjects are cylinders having solid circumferential sidewalls.
 9. Theapparatus of claim 3 wherein the disk includes a plurality of holes thatdefine a plurality of different sets of lug nut patterns so as to allowthe plurality of cup-shaped objects to be rigidly fixed to the disk inlocations that correspond with the lug nut pattern of the tire/hubassembly of the vehicle that the apparatus is removably attached to. 10.The apparatus of claim 9 wherein the plurality of holes are slot-shaped.11. The apparatus of claim 3 wherein the floating center shaft assemblyincludes a weight stabilization assembly attached thereto forstabilization of the single IMU during motion of the vehicle.
 12. Theapparatus of claim 3 wherein the floating center shaft assembly includesan airfoil stabilizing structure attached thereto for stabilization ofthe single IMU during motion of the vehicle.
 13. The apparatus of claim3 wherein the single IMU includes a Hall effect sensor, and the diskincludes a pair of magnets mounted thereon in an opposed manner a secondfixed radial distance from the radial center of the disk, the Halleffect sensor and the magnets being used to measure rotational speed ofthe apparatus during motion of the vehicle.
 14. The apparatus of claim 3wherein one or more of the cup-shaped objects includes a magnet fixedlymounted at an end of the cup-shaped objects proximate to the disk so asto magnetically engage with one of the lug nuts when the apparatus isattached to the tire/hub assembly of a vehicle, and thereby inhibit theapparatus from coming off of the vehicle when the vehicle is in motion.